1. Field of the Invention
The present invention relates to a technology to absorb the interfacial roughness at the interface between an insulator film and a wiring line of a semiconductor device, or the like.
2. Description of the Related Art
While increase of electric power consumption in a semiconductor device due to leakage current into an insulator film for a wiring layer has been known, effect of the leakage on a whole device was small in the generations when the distance between two wiring lines of a semiconductor device exceeded 1 μm. However, when the distance between two wiring lines is not more than 1 μm, effect on the electric power consumption will be larger due to the smaller distance between two wiring lines and increase of the wiring scale, and particularly when circuits are formed with a distance between two wiring lines of not more than 0.1 μm as will be expected, such leakage current between two wiring lines will greatly influence the properties and life of a device.
Currently, the damascene method is employed for forming wiring lines in a semiconductor device wherein grooves in the shape of the wiring lines are first formed in an insulator film by etching, and copper wiring lines are formed there through plating. However, since the insulator film is inevitably damaged during the etching of the damascene method, increase of leakage caused by the damage inside the insulator film, degradation in the TDDB (time-dependent dielectric breakdown) properties due to the roughness of the surface of the grooves for wiring, etc. will occur, significantly causing the degradation in the yield and reliability in the manufacture of semiconductor devices.
Under these circumstances, it is needed to restrain generation of the damage during the etching for forming grooves for wiring (or wiring grooves), to perform surface treatment so as to decrease the leakage after the etching, or the like.
As a surface treatment to suppress the etching damage, a treatment to make the grooves for wiring after etching hydrophobic is in practice. For example, it is possible to decrease the amount of water adsorbed to the surface which is caused by the etching damage, and accordingly, suppress degradation of properties such as increase of dielectric constant due to water, when a method to make hydrophobic the surface of a silica type coating film after etching, or like is employed {see Japanese Unexamined Patent Application Publication Nos. H6-267946 (claims), 2004-511896 (claims), 2004-513503 (claims) and 2004-292304 (claims)}.